The objective of the proposed research is to identify early in gestation changes in vitamin B-6 nutritional status of women who may be at risk of a deficiency of the vitamin following long-term use of oral contraceptives (OCA). Sixty-four women in the 18th week of gestation and who have not used OCA at any time previous to conception, will serve as the control group. Subjects will be randomly assigned to four groups to receive supplements of 2.5, 5, l0, or 15 mg pyridoxine/day. Another group of 64 subjects, at the same stage of gestation as the controls, and who have used OCA for 3 years or longer, will be randomly divided into four groups to receive 5, 10, 15 or 20 mg supplements of pyridoxine daily. To determine the relative effects of the different levels of vitamin B-6 supplementation, concentrations of total vitamin B-6 and pyridoxal phosphate will be measured in maternal plasma at 5 months gestation, at delivery and at 6 weeks postpartum and in cord plasma. Total vitamin B-6 content in milk will be measured on days 14, 28 and 42 postpartum. An effort will be made to determine whether the low levels of vitamin B-6 which have been observed in biological fluids, including cord blood and milk, of long-term OCA users can be normalized by supplementation with the vitamin beginning in early gestation.